During the 2nd continuation year of this project the work will examine the effects of catecholamine depletion on the altered responses of alpha-adrenergic, beta-adrenergic and dopamine-sensitive adenylate cyclases in posterior cerebral cortex from guinea pig and rat. This will be compared with corresponding data on cyclic AMP accumulation in chopped cerebral cortex tissue. Interactions with adenosine receptors, calcium ions and guanine nucleotides will also be examined.